US20030166339A1 - CMP system for metal deposition - Google Patents

Abstract

A system for dished metal redevelopment by providing a metal deposition solution at an interface between a moving semiconductor wafer and a moving polishing pad, which deposits metal onto dished metal in trenches in a layer of an interlayer dielectric; and by polishing the wafer with a relatively reduced polishing pressure to polish metal being deposited. A polishing fluid is disclosed for use in a CMP polishing system, the polishing fluid being a metal deposition solution for dished metal redevelopment.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a division of U.S. patent application Ser. No. 09/952,268, filed on Sep. 14, 2001, now abandoned, which claims the benefit of U.S. provisional patent application serial No. 60/233,018, filed Sep. 15, 2000.[0001]
FIELD OF THE INVENTION
• The invention relates to a system for polishing a semiconductor wafer, and more particularly, to a system for polishing while minimizing metal dishing in trenches in a semiconductor wafer.[0002]
BACKGROUND OF THE INVENTION
• A semiconductor wafer of silicon is manufactured with a layer of an interlayer dielectric, ILD, which can be a dielectric, such as, silica including SiO[0003]₂and TEOS, and further, such as, a low K dielectric. The ILD is suitable as base on which multilevel integrated circuits are to be fabricated. Metal filled trenches are fabricated in the ILD, for example, by a damascene process. Metal, such as, copper, in the trenches, and provides circuit interconnects. A thin barrier film, for example, tantalum, meaning elemental tantalum or tantalum alloy including tantalum nitride, between the copper metal and the ILD, provides a barrier to migration of the metal into the ILD. The barrier film covers the surface of the ILD including the trenches. The barrier film and a thin film of the copper metal are deposited in succession, for example, by successive chemical vapor deposition processes, followed by an electroplating process for depositing copper metal to fill the trenches. Copper metal covers the barrier film, and fills the trenches to provide circuit interconnects. The successive layers of the barrier film and copper metal cause the wafer to have a topography of peaks and valleys that require polishing to achieve a polished planar surface that is suitable as a base for integrated circuits. The wafer may comprise a standard test wafer, on which are performed tests for the effectiveness of polishing operations.
• The wafer is polished by a polishing system known as CMP, referred to as either or both, chemical-mechanical planarization and chemical-mechanical polishing. The CMP system moves the wafer against a moving polishing pad, and uses a combination of the moving polishing pad with polishing fluids at an interface with the wafer being polished, to remove the metal films by polishing pressure and chemical reaction of the metal films to the polishing fluid. According to accepted practices, a first step polishing operation is performed to remove the copper metal to the level of the underlying barrier film. Thereby, a test wafer is provided, having a top layer of barrier film, and further having trenches in an underlying ILD. The trenches contain metal that provide circuit interconnects. Further, the metal in the trenches are dished as a result of the first step polishing operation. The first step polishing operation is followed by a second step polishing operation that removes the barrier film to the surface of the underlying ILD, and which further results in the ILD being polished with a mirror-like, polished planar surface suitable for subsequent fabrication of integrated circuits. Further, the wafer is left with metal in the trenches to provide circuit interconnects. The metal in the trenches are dished as a result of being subjected to the second step polishing operation.[0004]
• The CMP polishing system would desirably result in a polished planar wafer surface without residual metal films on the polished surface of the ILD, and with all of the trenches having metal at heights that are even with the level of the polished surface. However, chemical reaction and mechanical friction, applied by the polishing operation results in undesired removal of metal from the trenches, referred to as dishing. Further, the wafer can be subjected to excessive polishing, to ensure complete removal of metal from the ILD surface, which results in erosion of the ILD surface. Excessive polishing can cause undesired rounding of the corner edges of the trenches, altering critical dimensions of the circuit interconnects in the trenches.[0005]
• A long existing need exists for a CMP system that minimizes, dishing of circuit interconnects in trenches, erosion of an ILD surface and rounding of corner edges of the trenches.[0006]
SUMMARY OF THE INVENTION
• The invention pertains to a system for dished metal redevelopment, DMR, that minimizes dishing. The invention provides a system for dished metal redevelopment of a semiconductor wafer by moving a surface of the wafer against a moving polishing pad, the system comprising the steps of: providing a plating solution at an interface between the wafer and the polishing pad, which redevelops dished metal in dished trenches in an interlayer dielectric, ILD, of the wafer.[0007]
• Dished metal redevelopment means that metal is deposited onto dished trenches, of a semiconductor wafer, by depositing metal onto the dished trenches; and polishing the wafer with a relatively reduced polishing pressure to polish the metal being deposited onto the dished trenches. The dished trenches contain dished metal resulting from previous manufacturing operations, such as, an electroplating process that has filled the trenches with metal, followed by a CMP polishing operation that has caused dishing of the dished metal in the dished trenches.[0008]
• An advantage of the invention resides in depositing metal onto dished trenches to redevelop the dished metal in the dished trenches, which minimizes dishing. A further advantage resides in depositing metal onto dished trenches to redevelop the dished metal in the dished trenches, which minimizes dishing, while simultaneously polishing by a CMP process to polish the metal being deposited. A further advantage resides in depositing metal onto dished trenches to redevelop the dished metal in the dished trenches, which minimizes dishing, while simultaneously polishing a wafer by a CMP process to remove a layer of metal from an underlying surface, and to polish the underlying surface and the metal being deposited. According to further advantages of the invention, erosion of an ILD is minimized, and rounding of the trenches is minimized, when polishing the metal being deposited on dished trenches during a polishing operation.[0009]
• A further aspect of the invention resides in, a polishing fluid for use in dished metal redevelopment by a CMP polishing operation wherein, a moving semiconductor wafer is urged against a moving polishing pad, the polishing fluid comprising: a metal deposition solution for depositing metal onto dished trenches in said wafer during said CMP polishing operation.[0010]
DESCRIPTION OF THE DRAWINGS
• Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, according to which;[0011]
• FIG. 1 is a diagrammatic view of a cross section of a semiconductor wafer having a copper metal layer removed to the level of an underlying barrier film of tantalum, and trenches imbedded with copper metal providing circuit interconnects;[0012]
• FIG. 2 is a diagrammatic view, similar to FIG. 1, disclosing a semiconductor test wafer having a having a layer of ILD with a polished surface, and dished copper metal in a dished trench in the ILD, which may be SiO[0013]₂, TEOS or a low K dielectric;
• FIG. 3 is a graph disclosing measurements of a surface height profile of a test wafer prior to deposition of metal onto dished metal in dished trenches;[0014]
• FIG. 4 is a spreadsheet of the measurements shown graphically in FIG. 3;[0015]
• FIG. 5 is a graph disclosing measurements of a surface height profile of a test wafer with copper metal deposited onto dished metal in dished trenches;[0016]
• FIG. 6 is a spreadsheet of the measurements shown graphically in FIG. 5;[0017]
• FIG. 7 is a diagrammatic view, similar to FIG. 1, disclosing a test wafer with a barrier film of tantalum covering a layer of ILD, and further disclosing a dished trench onto which is diagrammatically shown a deposit of copper metal applied by an electroless plating solution being used as a polishing fluid in a CMP polishing operation to remove the tantalum;[0018]
• FIG. 8 is a diagrammatic view, similar to FIG. 2, disclosing a test wafer having a layer of ILD with a polished surface, following a CMP polishing operation to remove a barrier layer of tantalum, and using a polishing fluid comprising a metal deposition solution that minimizes dishing of metal in a dished trench in the ILD.[0019]
DESCRIPTION OF THE EMBODIMENTS
• Three opportunities are provided for dished metal redevelopment by depositing metal onto dished metal in dished trenches of a wafer to replace metal that has been removed from the dished trenches by a polishing operation.[0020]
• (1). One opportunity for dished metal redevelopment by depositing metal onto dished trenches is presented by a wafer that has a polished and planarized surface of an ILD, and dished metal in trenches of the ILD. Such a wafer would benefit by having metal deposited onto the dished metal, which would raise the level of the metal in the trenches and minimize dishing. According to an embodiment of the invention, a metal deposition operation is performed on such a wafer, while at the same time, polishing the wafer with a reduced polishing pressure, to deposit metal onto the dished metal in the trenches, which replaces metal that has been removed from the trenches by a previous CMP polishing operation, and to raise the level of the plated metal in the trenches to a relative peak in the topology of the wafer. The relative peak is removed and planarized by polishing with the reduced polishing pressure. Experiments have been conducted, and are described hereafter.[0021]
• (2). A second opportunity for dished metal redevelopment by depositing metal onto trenches is presented by a wafer that has a top layer of a metal, such as, copper, covering an underlying barrier film, and the wafer needs CMP polishing to remove the top layer of copper metal from the underlying barrier film, and to polish the surface of the barrier film to a planar surface. According to the invention, a CMP polishing operation is performed on a wafer for a time period sufficient to remove copper metal from an underlying barrier film on an ILD, which further causes metal dishing in trenches in the ILD, and, further, the polishing operation is continued with a reduced polishing pressure and in concert with a metal deposition solution, which deposits metal onto dished trenches in the ILD, and which polishes the wafer at such reduced polishing pressure to remove metal that becomes deposited on the barrier film, and which exposes the surface of the barrier film.[0022]
• (3). A third opportunity for dished metal redevelopment by depositing metal onto trenches is presented by a wafer that has a barrier film covering an underlying ILD, and that has dished metal in trenches in the ILD. The wafer needs CMP polishing to remove the barrier film from the ILD, and to polish the ILD to a planar surface. According to the invention, a CMP polishing operation is performed to remove a barrier film from the underlying ILD and to polish the ILD to a planar surface. According to the invention, a CMP polishing operation is performed with a pH basic polishing fluid to remove a barrier film from an underlying ILD, and to polish a surface of the ILD to a planar surface, and the polishing fluid is a pH basic metal deposition solution which deposits metal onto dished metal in dished trenches in the ILD. Metal is deposited onto dished metal by the metal deposition solution at the same time that CMP polishing occurs to cause dishing. The dishing that would be caused by the CMP polishing is minimized. Experiments have been conducted, and are described hereafter.[0023]
• FIG. 1, discloses a first opportunity, during manufacture of a wafer for providing a system for dished metal redevelopment by depositing metal onto dished metal in dished trenches. FIG. 1 discloses, a portion of a[0024]test wafer1 comprising, asilicon substrate2 and a layer of anILD3, for example, TEOS, having therein, one ofmultiple trenches4 in whichmetal5 is contained to provide a circuit interconnect. Further, thewafer1 comprises, abarrier film6, for example, of tantalum covering theILD3.
• The[0025]wafer1 disclosed in FIG. 1 was subjected to a previous CMP polishing operation that was intended to polish thebarrier film6 to a planar surface, and to polish themetal5 in thetrench4 to the same height as that of thebarrier film6. However, as further disclosed by FIG. 1, a condition known as dishing has resulted from some of the concave dishedmetal5 in the dishedtrench4 being removed during polishing, which causes the dishedmetal5 in the dishedtrench4. Dishing is undesirable for adversely affecting the critical dimensions of the circuit interconnects, and for causing variations in the planarity of thewafer1. Accordingly, there exists a need for dished metal redevelopment, which minimizes metal dishing.
• FIG. 2 discloses a second opportunity, during manufacture of a wafer, for providing a system for dished metal redevelopment by depositing metal onto dished metal in dished trenches. FIG. 2 discloses, a portion of a[0026]test wafer1 comprising, asilicon substrate2 and a layer of anILD3, for example, TEOS, having therein, one ofmultiple trenches4 in whichmetal5 is imbedded to provide a circuit interconnect. Further, the wafer comprises, abarrier film6 between theILD3 and dishedmetal5 in the dishedtrench4. TheILD3 has been polished with a planar surface, which has removed a barrier layer from theunderlying ILD3.
• The invention has resulted from a series of experiments, described hereafter, discloses a third opportunity, during manufacture of a wafer, for providing a system for depositing metal onto dished metal in dished trenches.[0027]
Experiment 1 UsingMcDermit Hyspec 2
• [0028]Experiment 1 was conducted to determine whether a known plating solution would deposit copper metal onto dished metal in dished trenches of a test wafer. A test wafer was provided, as having a top layer of copper removed by CMP polishing, and a barrier film of tantalum nitride removed by CMP polishing to the level of an ILD of TEOS. Dished trenches in the ILD contained dished copper metal.
• The experiment was conducted by immersing the test wafer in a metal deposition solution at room temperature, according to which, a plating solution, adjusted to pH basic, was applied to the test wafer. The plating solution is commercially available from Shipley Chemical Corporation, and known as,[0029]McDermit Hyspec 2, of the Nanoplating 2000 Series. Sugar was added as a slow reacting, reducing agent. The results of the experiment were unsuccessful in depositing a sufficient thickness of metal in the trenches within a time frame of approximately three minutes.
Experiment 2 Using a Known Plating Solution
• [0030]Experiment 2 was conducted to determine whether a known plating solution would deposit copper metal onto dished metal in dished trenches of a test wafer, using a known electroless copper plating solution, as described in U.S. Pat. No.5,965,211. The test wafer was similar to the test wafer, as provided inExperiment 1.
• The experiment was conducted by immersing a test wafer in the solution, adjusted to pH basic, for an observed time period. Thereafter, the test wafer was cleaned in deionized water.[0031]
• The experiment was successful, in that the known electroless copper plating solution successfully deposited an acceptable thickness of copper in dished trenches of a test wafer within a few minutes duration.[0032]
Experiment 3 Using a Known Plating Solution
• [0033]Experiment 3 was conducted to determine whether a known plating solution would deposit copper metal onto dished metal in dished trenches of a test wafer, using a known electroless copper plating solution, as described in, Metal Finishing Guidebook. The test wafer was similar to the test wafer, as provided inExperiment 1.
• The experiment was conducted by immersing a test wafer in the solution, adjusted to pH basic, for an observed time period. Thereafter, the test wafer was cleaned in deionized water.[0034]
• The experiment was successful, in that the known electroless copper plating solution successfully deposited an acceptable thickness of copper in dished trenches of a test wafer within a few minutes duration.[0035]
Experiment 4
• [0036]Experiment 4 refers to a series of experiments that were conducted to determine whether different metal deposition solutions would deposit copper metal onto dished metal in dished trenches of a test wafer. In addition, the experiments were conducted to determine whether or not any of the tested metal deposition solutions is suitable for use as a slurry, or polishing fluid, in a CMP polishing operation to remove a barrier layer of tantalum and polish the underlying ILD with a planar polished surface. Further, at least one of the experiments was conducted to use a metal deposition solution as a slurry, or polishing fluid, in a CMP polishing system that operated to remove a barrier layer of tantalum, and to polish the underlying ILD with a planar polished surface.
• Each test wafer was similar to the test wafer, as provided in[0037]Experiment 1. The series of experiments used different metal deposition solutions, RD-1 through RD34, as described in each of: Table 1, Table 2 and Table 3. These Tables are incorporated in the present description as an Appendix of the present description.
Table 1
• Table 1 has three columns for categorizing rows of data entered in the Table 1. Column one of Table 1 is named, “Solution” for categorizing data entries by different metal deposition solutions that are identified as RD-1 through RD 36, as entered in column one of Table 1. The second column is named “Test subject” for categorizing data entries according to remarks pertaining to the constituents of the solutions. The third column is named “Observation” for categorizing data entries according to the observed results that occurred when test wafers were exposed to, and reacted with, the solutions.[0038]
• The data entries corresponding to metal deposition solutions RD1-RD5 in Table 1, pertain to different solutions that were formulated with combined constituents: CuSO[0039]₄, NH₃Cl and sugar as a leveler, instead of formaldehyde as a reducing agent, and an adjusted pH>9, and/or an adjusted pH>11, as adjusted with KOH. As recorded in column three, the pH was observed to drift, or the solution changed color or precipitates were observed. Accordingly, the solutions RD1-RD5 were unsatisfactory in depositing metal in dished trenches of test wafers.
• The date entries corresponding to metal deposition solutions RD-6 and RD-7 in Table 1,pertain to experiments wherein, different electroless plating solutions were formulated, with a reducing agent in the form of formaldehyde. The data entries indicate that solutions RD-6 and RD-7 were unsatisfactory in depositing metal in dished trenches of test wafers.[0040]
• The data entries corresponding to metal deposition solutions RD-8 through RD-36, all pertain to solutions using formaldehyde and Potassium Ferrocyanide, as action initiators and as accellerators. Each of the solutions RD-8 through RD-36 used a metal deposition solution, for example, an electroless copper plating solution having combinations of constituent chemical parts that varied in combination and in relative concentrations. The constituent parts were selected from the constituent parts that comprised:[0041]
• (1) Ethanolamine and Ethanolamine ACS reagent,[0042]
• (2) Tri-ethanolamine,[0043]
• (3) Formaldehyde and Formaldehyde sodium bisulfate, as reducers,[0044]
• (4) NH[0045]₄Cl, Ammonium Chloride as a leveler,
• (5) Ethylene-diamine-tetra-acetic acid (EDTA) as a complexing agent,[0046]
• (6) D-iso-ascorbic acid (IAA) as a reducer,[0047]
• (7) Nitrilo-tri-acetic acid,[0048]
• (8) Isophthalic acid,[0049]
• (9) 2,2′-Dipyridyl,[0050]
• (10) Potassium ferrocyanide,[0051]
• (11) Citric acid (CA) as a complexing agent,[0052]
• (12) Copper sulfate pentahydrate (Cu SO[0053]₄), and
• (13) CaH2.[0054]
• Other such constituent parts comprised:[0055]
• (1) Copper chloride,[0056]
• (2) Ammonium citrate,[0057]
• (3) Tartaric acid,[0058]
• (4) Potassium ferrocyanide trihydrate,[0059]
• (5) 2-Mercaptobenzothiazole (MBT),[0060]
• (6) Sodium chloride,[0061]
• (7) Potassium chloride,[0062]
• (8) Phthalic acid, and[0063]
• (9) Polyetheylene glycol.[0064]
• The experiments were conducted at room temperature. In each solution, pH was adjusted with Potassium hydroxide to a pH within a range 11.30 to 12.60. The adjusted pH>9 was found to be required for an acceptable metal deposition rate of sufficient rapidity, to obtain, for example, 500A° thickness of deposited metal in 5 minutes. An adjusted pH>11 increases the acceptable metal deposition rate.[0065]
• The experiments indicate that an acceptable metal deposition rate onto dished trenches is accomplished by a solution having the chemical constituent parts; Potassium ferrocyanide, Copper sulfate or Copper chloride providing a source of copper ions, Ammonium citrate or NH[0066]₃ETDA and a pH>9 and when polishing tantalum, a preferred pH>11.
Table 2
• Table 2 in the Appendix, contains additional data entries corresponding to metal deposition solutions RD-8 through RD-36. Table 2 has three columns for categorizing rows of data entered in the Table 2.[0067]
• Column one of Table 2 (and part of Column two) is named, “Slurry” for categorizing data entries by different metal deposition solutions that are identified as RD-1 through RD 36, as entered in column one of Table 1. The term, “Slurry” refers to a polishing fluid that is used in a CMP polishing system. The experiments were conducted to determine whether or not a metal deposition solution is suitable as a slurry, or polishing fluid, in a CMP polishing system.[0068]
• An upper part of Column two of Table 2 is named “Total” to indicate the total grams “(g)” of different solutions that were used to deposit copper metal. Columns three through sixteen identify the constituent chemical parts of such different solutions, measured in grams “(g)”; and the percentages “(%)” in columns three through sixteen represent the concentrations, or purities, of the constituent chemical parts.[0069]
• Further, Columns three through sixteen in a lower part of Table 2, below the grams “(g)” in columns three through sixteen, the percentages by weight percent of the constituent chemical parts are indicated. Column seventeen in the lower part of Table 2 is named “Final pH” to indicate the adjusted pH of the solutions, adjusted with KOH. Column eighteen is named “actual pH” to indicate the pH of the solutions prior to the pH being adjusted.[0070]
• The adjusted pH>9 was found to be required for an acceptable metal deposition rate of sufficient rapidity, to obtain, for example, 500A° thickness of deposited metal in 5 minutes. An adjusted pH>11 increases the acceptable metal deposition rate.[0071]
• Further, a lower part of Column nineteen, Table 2, is named “Observation,” for categorizing data entries according to the observed results that occurred when test wafers were exposed to, and reacted with, the solutions.[0072]
Table 3
• Table 3, Appendix, records measurements of metal deposits on the surface of a test wafer having metal deposited by Solutions RD8 through RD 36. Column one, named “RD-formula” identifies the metal plating solutions RD8 through RD36, as further identified in Table 1 and Table 2. The measurements were performed by a Vecco profilometer, commercially available from the Veeco company.[0073]
• Column one of Table 3, records respective plating solutions RD-08 through RD-30. Column two, of Table 3, named “Pre,” records measurements in height of the metal in trenches, relative to the height of the TEOS providing an ILD; prior to exposure of the test wafer to the respective plating solutions RD-8 through RD-36, as recorded in Column one. Column two is divided into subcategories, “ASH,” meaning Average Standard Height, and “TIR” meaning Total Indicated Result from the lowest measured height to the highest measured height, which was measured from a reference plane referenced at zero. The lowest measured height, in the “Pre” category of test measurements, corresponds to the depth of dished metal in the trenches, of test wafers prior to exposure to respective plating solutions. The highest measured height corresponds to the height of TEOS providing an ILD of the test wafers prior to exposure to respective plating solutions.[0074]
• Column three of Table 3, named “Post,” records measurements in height of the metal in trenches, relative to the height of the TEOS providing an ILD; subsequent to exposure of the test wafer to the respective plating solutions RD-8 through RD-36.[0075]Column 3 is divided into subcategories, “ASH,” meaning Average Standard Height, and “TIR” meaning Total Indicated Result from the lowest measured height to the highest measured height, measured from a reference plane referenced at zero.
• Column4, of Table 3, named “Delta Ash” records measurements of the differences in “Ash” of metal in trenches of the test wafers, due to, either subtractive etching or additive deposition, of metal in trenches of the test wafers, caused by exposure of the test wafers to the respective solutions RD-08 through RD-36. Some of the measurements are negative, as indicated by respective minus signs, which indicate that etching, instead of additive deposition, was observed. The measurements in[0076]Column 4, Table 3, that are positive, as indicated without minus signs, indicate that metal was successfully deposited on the metal in the trenches.
• Thus, Table 3 indicates that some of the solutions RD-08 through RD-36 were successful in depositing copper metal onto metal in trenches of the test wafers, and particularly, in depositing metal at an acceptable deposition rate that is equal to or greater than 100A° per minute for an elapsed time of five minutes.[0077]
• FIG. 3 graphically records measurements representing differences in the height of a test wafer having a number of dished trenches that are disposed between two reference points “R” and “M” spaced apart on the surface of the test wafer. The measurements are further represented, as disclosed by FIG. 4, in a spreadsheet. The measurements are further represented, as recorded in Table 3, by the “Pre” data corresponding to the solution RD-30. Additional graphs exist for other metal solutions. For purposes of description herein, such additional graphs are not disclosed herein.[0078]
• FIG. 5 graphically records measurements representing differences in the height of the test wafer subsequent to the test wafer having been exposed to the metal deposition solution RD-30, as disclosed by Tables 1, 2 and 3. The measurements are further represented, as disclosed by FIG. 6, in a spreadsheet. The measurements are further represented, as recorded in Table 3, by the “Post” data corresponding to the solution RD-30. Additional graphs exist for other metal solutions. For purposes of description herein, such additional graphs are not disclosed herein.[0079]
• Previous to conducting the experiment, the “Pre” data is depicted in the graph, FIG. 3, which discloses the ILD surface being measured as peaks in the graph, and which further discloses the dished metal in trenches being measured as valleys in the graph. The dished metal was below the level of the ILD. Following immersion of the test wafer in the solution RD-30, copper metal was deposited on the dished metal at an acceptable deposition rate. The “Post” data is depicted in the graph, FIG. 5, which discloses the ILD surface being measured as valleys in the graph, and which further discloses the deposited metal onto the trenches having a thickness that extends above the height of the ILD. FIG. 5 graphically indicates that copper metal has deposited on the dished metal in dished trenches of a test wafer. Accordingly, Table 3 provides a notation “Re-dep” as an indication that solution RD-[0080]30 provides an acceptable deposition of metal. Each of the other metal deposition solutions that provides an acceptable deposition is indicated with a similar notation “Re-dep” in Table 3.
• The invention resides in using a metal deposition solution to deposit metal onto dished metal in dished trenches, and further, using such a solution as a polishing fluid for a CMP polishing operation to polish a wafer to a polished planar surface. For example, any of the solutions indicated with the notation “Re-dep” would be candidates for use as such a polishing fluid. According to the invention, metal dishing is minimized by providing a CMP polishing system that deposits metal onto dished metal in dished trenches.[0081]
• With reference to FIG. 2, an opportunity to deposit copper metal during a polishing operation will now be discussed. For example, with reference to FIG. 2, A CMP polishing operation operates to remove a top layer of tantalum, barrier film, from the underlying ILD, TEOS using a relatively high polishing pressure in the presence of a polishing fluid, which removes the barrier film, and exposes the ILD and leaves dished metal in each dished trench. The CMP polishing operation is continued by polishing with a reduced polishing pressure in the presence of a metal deposition solution, such as a metal deposition solution, as appearing in Tables 1 and 2, to deposit metal onto dished metal in each dished trench, while polishing at a reduced polishing pressure polishes the surface of the deposited copper metal. The deposited metal will replace the metal removed by polishing with the relatively higher polishing pressure. Further, the deposited metal will be polished by the relatively lower polishing pressure in the presence of the metal deposition solution being used as the polishing fluid. Metal deposition is performed during CMP polishing with a reduced polishing pressure, while providing a metal deposition solution, which deposits metal onto the metal in the dished trench. The trench will have a metal deposit with a slightly dished surface caused by polishing during deposition. Accordingly, metal is deposited in the trench to replace metal that has been removed by polishing. The deposited metal in the trench has only a slightly dished surface that results from polishing simultaneously occurring with deposition of the metal. The deposited metal in each trench ensures that sufficient metal is present in the trench to provide a circuit interconnect that meets critical dimensional requirements, and that avoids a localized defect in the wafer due to excessive dishing.[0082]
• With reference to FIG. 7, a further opportunity to deposit copper metal during another polishing operation will now be discussed. For example, with reference to FIG. 7, A CMP polishing operation operates to remove a top layer of copper metal from the[0083]underlying barrier film6 using relatively high polishing pressure in the presence of a known copper removing, polishing fluid, which removes the copper metal, and exposes thebarrier film6, and leaves dishedmetal5 in each dishedtrench4. The polishing pressure used in a CMP polishing operation can be adjusted to be in excess of seven pounds per square inch, which is used, for example, to remove a layer of copper metal from awafer1. The polishing pressure used in a CMP polishing operation can be adjusted to be between six pounds per square inch and three pounds per square inch, which is used, for example, to remove alayer6 of tantalum metal from awafer1.
• According to the invention, the CMP polishing operation is continued by polishing with a reduced polishing pressure, adjusted to be less than three pounds per square inch, in the presence of a metal deposition solution, such as a metal deposition solution, as appearing in Tables 1 and 2, to deposit metal, indicated by a phantom outline[0084]5A, onto dishedmetal5 in each dishedtrench4, while polishing at a reduced polishing pressure polishes the surface of the deposited copper metal Sa. The solution selectively deposits copper metal Sa onto dishedcopper5, rather than onto thetantalum6. The depositedmetal5awill replace themetal5 removed by polishing with the relatively higher polishing pressure, which results in dished metal redevelopment. Further, the depositedmetal5 will be polished by the relatively lower polishing pressure in the presence of the metal deposition solution being used as the polishing fluid. Metal deposition is performed during CMP polishing with a reduced polishing pressure, while providing a metal deposition solution, whichdeposits metal5aonto the dishedmetal5 in the dishedtrench4. Thetrench4 will have ametal5 with a slightly dished surface caused by polishing during deposition. Accordingly,metal5ais deposited in the trench to replacemetal5 that has been removed by polishing. The depositedmetal5aonto thetrench4 has only a slightly dished surface that results from polishing simultaneously with deposition of themetal5a. The depositedmetal5aonto eachtrench4 ensures that sufficient metal is present in thetrench4 to provide a circuit interconnect that meets critical dimensional requirements, and that avoids a localized defect in thewafer1 due to excessive dishing.
• With reference to FIG. 7, another opportunity to deposit copper metal during a polishing operation will now be discussed. By way of example, the thickness of the dished[0085]metal5 in eachtrench4 is at least 600 A° minimum, which is the minimum thickness for a circuit interconnect that meets critical dimensions. A further CMP polishing operation is required to remove the tantalum,barrier film6, to expose theunderlying ILD3, and to polish theILD3 with a planar polished surface. However, further dishing of the dishedmetal5 in eachtrench4, as caused by the further CPM polishing operation would be undesired.
• According to the invention, a CMP polishing operation operates to remove a top layer of tantalum,[0086]barrier film6, from theunderlying ILD3, TEOS, using a relatively higher polishing pressure in the presence of a polishing fluid, which removes thebarrier film6, exposing theunderlying ILD6 and leaving dishedmetal5 in each dishedtrench4. The polishing fluid is a metal deposition solution, such as disclosed in Tables 1, 2 and3, to depositmetal5aonto the dishedmetal5 in each dishedtrench4. The solution selectivelydeposits copper metal5aonto dishedcopper metal5 in each dishedtrench4. The metal deposition solution has an adjusted pH>9 to ensure an acceptable metal deposition rate. In addition the solution, by having a relatively high pH will ensure chemical dissolution of thebarrier layer6, the barrier layer being removed by a combination of mechanical removal by polishing and chemical removal by dissolution. The polishing fluid contains abrasive colloidal silica of 15% by weight proportion, for enhancing the time based rates of removal and polishing.
• Polishing with a relatively higher polishing pressure, 3-7 pounds per square inch, removes the top layer of tantalum at a relatively rapid rate, while[0087]copper metal5ais being deposited in thetrench4, to expose theunderlying ILD3. Polishing continues with a reduced polishing pressure to polish theunderlying ILD3 to a planar polished surface. FIG. 8 discloses awafer1 that has been polished sufficiently to remove all of the tantalum,barrier film6, exposing apolished surface3aof theunderlying ILD3.
• FIG. 8 diagrammatically shows that a potential thickness of deposited[0088]copper metal5a, in the absence of polishing, would extend themetal5 in thetrench4 to a height above the height of theILD3. Such an occurrence is further disclosed by FIG. 6 that discloses measurements ofmetal5aintrenches4 extended to a height above the height of the TEOS,barrier film6, following metal deposition according to experiment RD-30. However, the polishing operation removes the depositedcopper metal5a, such that, as shown in FIG. 8, the polishing operation has removed all depositedcopper metal5ain its entirety, which leaves the dishedmetal5 in eachtrench4 with the required thickness of at least 600 A° minimum, which is the minimum thickness for a circuit interconnect that meets critical dimensions. According to an advantage of the invention, complete removal of the depositedmetal5aby CMP polishing, eliminates the depositedmetal5atogether with all defects in the depositedmetal5a, because of excessively large grain boundaries, or because of interruptions in the deposit, or because of copper complexing ions in the deposited copper metal.
• Another advantage of removing all of the deposited[0089]metal5aduring CMP polishing of thewafer1 shown in FIGS. 7 and 8, is that dishing of themetal5 in thetrench4, as shown in FIG. 8, remains unchanged from that shown in FIG. 7, without the dishing being increased by the polishing operation that removes thetantalum barrier film6. Accordingly, dishing is minimized by the polishing operation, according to the invention. For example, FIG. 8 diagrammatically shows, inphantom outline5a, the potential thickness of depositedcopper metal5athat would extend the height ofmetal5 in thetrench4, in the absence of polishing. However, the polishing operation has removed all of themetal5adeposited by the metal deposition solution. By way of example, the polishing operation is performed with a reduced polishing pressure for an elapsed time of five minutes. Such polishing operation uses the metal deposition solution RD-36, as identified in each of Tables 1, 2 and 3, as a polishing fluid having an adjusted pH>11, and specifically pH=12. Further, the solution is used as a polishing fluid for CMP polishing, and has abrasive colloidal silica 15% by weight proportion of the constituent parts of the solution.
• The columns of Table 4 in the Appendix, identify the test wafer, the down force DF, the pressure BP, the Flow rate of the polishing fluid (metal deposition solution and abrasive particles), the speed of the Platen mounting the test wafer thereon, the speed of the Carrier on which the Polish Pad is mounted, the polishing time Pol. Time, the Slurry composition RD-36, and the type of Polish Pad used for polishing. The thickness of deposited[0090]metal5awould be approximately 500A° in the absence of polishing. However the polishing operation with a reduced polishing pressure has removed the depositedmetal5ain its entirety, without increasing the depth of the dishedmetal5 that was previously in thetrench4. The polishing operation prevents increased dishing of the dishedmetal5 in thetrench4 to provide a circuit interconnect that meets critical dimensional requirements. Further, the polishing operation avoids a localized defect in thewafer1 due to excessive dishing. Further, FIG. 8 diagrammatically shows, in phantom outline, theheight3bof theILD3 that is removed by polishing to a planarpolished surface3a. By way of example, 100 A° of the TEOS,ILD3, is removed by polishing to a planarpolished surface3a.
• An Appendix appears on seven following pages herein.[0091]
• Although preferred embodiments of the invention have been disclosed, other embodiments and modifications are intended to be covered by the spirit and scope of the appended claims.[0092]

  Appendix - Table 1

  Solution	Test subject	Obervation
  RD-1	tartaric and vanillin	pH 9.3 no re-dep
  RD-2	tartaric salicylaldehyde	pH drift from 10 to 8.9, no re-dep
  RD-3	ammonium citrate and vanillin	pH 11 etched Cu 200-300 A, NH3 from ammonium citrate etched
  RD-4	Citric and vanillin	pH 11, No etch no-redep, solution change color at pH 5.5-6 to yellowish color
  RD-5	Citric end vanillin	No re-dep:, pH drifted from 11 to 7.7
  RD-6	Formaldehyde, EDTA,	pH 12: overnight soak showed corrosion with no re-dep
  	potassium sodium tartrate
  RD-7	Formaldehyde, edta, sugar	initial pH at 9 solution percipitated
  	malic acid	with malic acid solution re-desolved: 600 A etched overnight
  RD-8	Formaldehyde, edta tartaric	re-dep overnight
  	NH4Cl sugar pH 9.5
  RD-9	ethanolamine. Formaldehyde	Re-dep 11,200A with 10 min soak
  	NH4Cl, ammonium citrate	photo showed dark material on top of Cu, bonding is weak
  	Potassium terrocyanide, pH 11.3
  RD-10	RD-9 with NaCl (minimize NH4)	Re-dep 100A with 5 min soak
  RD-11	RD-10 with no K ferrocyanide	Etched 100 A within 5 min at pH 11.3
  RD-12	triethanolamine, 2,2 diphridyl	bluish solution at pH 7.2-7.5 with percipitate
  		after adjusting pH to 12.6 solution re-desolved
  RD-13	RD-12 with IAA	greenish solution with percipitate at pH 7.2-7.5. After adjusting pH to 12.6 solution
  		re-desolved but small amount of black solid at the bottom
  RD-14	all ingrediaent	Brownish percipitate settle
  		Re-dep test suspended
  RD-15	RD-14 minus IAA	Etched 10 A within 5 min with no re-dep, solution stay same light blue
  RD-16	RD-15minus. Nitrilotriacetic acid	No re-dep or etch, solution stay same blue color
  RD-17	RD-16 minus edta	No re-dep or etch, solution stay same blue color
  RD-18	rd-17 minus 2,2'dipyridyl	spots of re-dep (14K A) within 5 min
  		un-even “spot” deposition
  RD-19	CaH2	Reacted violently when added to pH 12 solution
  		no re-dep
  RD-20	CA, dipyridyl	no re-cep
  RD-21	Ca, IAA	Precipitated brown FeOH
  RD-22	Triethanolamine, CA	spots of re-dep (44K A) within 5 min
  RD-23	Triethanolamine, IAA, dipyridyl, CA	Precipitated brown FeOH
  CA	Clean surface with	8000 re-dep (dark granular structure)
  RD-09	1.5% CA solution	Ammonium citrate used not CA
  CA	Clean surface with	300 re-dep spotty
  RD-10	1.5% CA solution	CA used
  CA	Clean surface with	500 re-dep spotty
  RD-18	1.5% CA solution	CA used
  CA	Clean surface with	300 re-dep spotty
  RD-22	1.5% CA solution	CA used
  RD-23	IAA	Precipitated brown FeOH
  RD-24	Low potassium ferrocyanide	Redep 2921A 5 min
  RD-25	low ammonium citrale	Redep 1051A 5 min
  RD-26	Isophthalic acid	Redep 4168A 5 min
  RD-27	sodium sulfite	Etch 102A 5 min
  RD 28	mercaptoacetic acid	Precipitated brown FeOH
  RD 29	Higher isophthalic .25%	Partial re-dep 8950A
  RD 30	Higher isophthalic .5%	Re-dep 4721 A
  RD 31	Higher isophthalic 1%	Re-dep 4379 A
  RD-32	lower sodium sulfite .25%	Isolated spots
  RD-33	lower sodium sulfite .1%	Re-dep 14282 A
  RD-34	lower sodium sulfite .05%	Re-dep 5069 A
  RD-35	Larger batch with higher NaCl	Polish 1st step wafer with 3292 and 3285 than polish with RD35 on politex pad
  RD-36	RD-35 + 1501-50 1:1 volume mix	Polish 1st step wafer with RD35 with 1501-50

• [0093]

  Appendix - Table 2

  99%

  37%

  98.0%

  100.0%

  98.0%

  99.0%

  99.0%

  99.0%

  99.0%

  99.5%

  99%

  B-

  Total

  Ethanol

  99%

  Formaid

  NH4CL(le

  EDTA (d

  IAA (red

  Nitrilotria-

  Isophith

  2,2'-Dipyr

  Postasium

  CA (cor

  CuSO4

  99%

  DIW

  part

  A-Part

  (conc.)

  Slurry

  (g)

  (g)

  Triethan

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  CaH2

  (g)

  (g)

  (g)

  (g)

  (g)

  A-part

  RD-8	999	0.00	0.00	2.97	1.02	2.00	0.00	0.00	0.00	0.00	0.00	0.00	1.01	0.00	992	999
  RD-9	1000	6.06	0.00	5.00	0.10	0.00	0.00	0.00	0.00	0.00	0.51	1.01	1.01	0.00	986	1000			0	30.0
  RD-10	1000	5.05	0.00	4.05	0.10	0.00	0.00	0.00	0.00	0.00	0.51	1.01	1.01	0.00	988	1000			0	30.0
  RD-11	1000	5.05	0.00	4.05	0.10	0.00	0.00	0.00	0.00	0.00	0.51	1.01	1.01	0.00	989	1000			0	30.0
  RD-12	500	0.00	0.75	2.03	0.05	0.00	0.00	0.00	0.00	0.13	0.13	0.00	0.51	0.00	496	500			0	30.0
  RD-13	500	0.00	0.76	2.03	0.05	0.00	0.51	0.00	0.00	0.13	0.13	0.00	0.51	0.00	496	500			0	30.0
  RD-14	500	2.53	0.00	2.03	0.05	0.25	0.51	0.51	0.00	0.10	0.25	0.00	0.51	0.00	493	500			0	30.0
  RD-15	500	2.53	0.00	2.03	0.05	0.25	0.00	0.51	0.00	0.05	0.25	0.00	0.51	0.00	494	500			0	30.0
  RD-16	500	2.53	0.00	2.03	0.05	0.25	0.00	0.00	0.00	0.05	0.25	0.00	0.51	0.00	494	500			0	30.0
  RD-17	500	2.53	0.00	2.03	0.05	0.00	0.00	0.00	0.00	0.05	0.25	0.00	0.51	0.00	495	500			0	30.0
  RD-18	500	2.53	0.00	2.03	0.05	0.00	0.00	0.00	0.00	0.00	0.25	0.00	0.51	0.00	495	500			0	30.0
  RD-19	500	2.53	0.00	2.03	0.05	0.00	0.00	0.00	0.00	0.00	0.25	0.50	0.51	0.51	494	500			0	30.0
  RD-20	500	2.53	0.00	2.03	0.05	0.00	0.00	0.00	0.00	0.05	0.25	0.50	0.51	0.00	494	500
  RD-21	500	2.53	0.00	2.03	0.05	0.00	0.51	0.00	0.00	0.00	0.25	0.50	0.51	0.00	−494	500
  RD-22	500	2.53	0.51	2.03	0.05	0.00	0.00	0.00	0.00	0.00	0.25	0.50	0.51	0.00	494	500
  RD-23	500	2.53	0.51	2.03	0.05	0.00	0.51	0.00	0.00	0.05	0.25	0.50	0.51	0.00	493	500
  																				30.0

  Ethanol-

  Triethanol-

  Formal-

  Nitrilotri-

  Potasium-

  CA

  amine

  amine

  dehyde

  NH4Cl

  EDTA

  IAA

  gacetic

  Isophthalic

  2,2'-

  ferro-

  (com-

  Final

  actual

  Slurry

  (basic)

  (basic)

  (reducer)

  (leveler)

  (complex)

  (reducer)

  acid

  acid

  Dipyridyl

  ayanide

  plexing)

  CuSO4

  CaH2

  other

  pH

  pH

  Obervation

  RD-8			0.110	0.100	0.2000							0.10		x		9.5	Tantanic 1 g sugar 5 g
  RD-9	0.6		0.185	0.010						0.0500	0.1000	0.10		x	12.20
  RD-10	0.5		0.150	0.010						0.0500	0.1000	0.10		x	11.30		NaCl
  RD-11	0.5		0.150	0.010							0.1000	0.10			11.30
  RD-12		0.15	0.150	0.010					0.0250	0.0250		0.10			12.60
  RD-13		0.15	0.150	0.010		0.1000			0.0250	0.0250		0.10			12.60
  RD-14	0.5		0.150	0.010	0.05	0.1000	0.1000		0.0200	0.0500		0.10			12.00	12.2	pH 8.8 prior to ph adjustment,
  																	color was clear at pH 8.8 turn
  																	slightly yellowish at pH 12,
  																	mixed color is brownish
  RD-15	0.5		0.150	0.010	0.05		0.1000		0.0100	0.0500		0.10			12.00	12.2	pH 9.2 prior to adjustment,
  																	yellow turn to light blue
  																	when Cuso4 added
  RD-16	0.5		0.150	0.010	0.05				0.0100	0.0500		0.10			12.00	12.5	pH 9.4 prior to adjustment,
  																	yellow turn blue when CuSO4
  																	added
  RD-17	0.5		0.150	0.010					0.0100	0.0500		0.10			12.00	12.0	pH 9.4 prior to adjustment,
  																	yellow turn darker blue
  																	when CuSO4 added
  RD-18	0.5		0.150	0.010						0.0500		0.10			12.00	12.2	pH 9.5 prior to adjustment,
  																	yellow turn dark blue when
  																	CuSO4 added
  RD-19	0.5		0.150	0.010						0.0500	0.1000	0.10	0.10		12.00	9.2/12	violet reaction to H2O even
  																	at high pH
  RD-20	0.5		0.150	0.010					0.0100	0.0500	0.1000	0.10			12.00	9.2/12
  RD-21	0.5		0.150	0.100		0.1000				0.0500	0.1000	0.10			12.00	8.8/12	precipitate FeOH brown color
  RD-22	0.5	0.1	0.150	0.010						0.0500	0.1000	0.10			12.00	9.2/12
  RD-23	0.5	0.1	0.150	0.010		0.1000			0.0100	0.0500	0.1000	0.10			12.00	9.0/12	precipitate FeOH brown color

  99%

  37%

  98.0%

  100.0%

  98.0%

  99.0%

  99.0%

  99.0%

  99.0%

  99.5%

  97%

  99%

  B-

  30.0%

  A-

  Total

  Ethanol

  99%

  Formaid

  NaCL(lev

  EDTA (d

  IAA (red

  sodium s

  Isophith

  2,2'-Dipyr

  Postasium

  NH4 cit

  Mercapt

  Cu-

  DIW

  part

  part A

  Part

  (conc.)

  Slurry

  (g)

  (g)

  Triethan

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  (g)

  SO4

  (g)

  (g)

  (g)

  (g)

  (g)

  A-part

  RD-24	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00	0.00	0.00	0.10	0.50	0.00	0.52	494	500			0	30.0
  RD-25	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00	0.00	0.00	0.25	0.25	0.00	0.52	494	500			0	30.0
  RD-26	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00	0.51	0.00	0.25	0.50	0.00	0.52	493	500			0	30.0
  RD-27	500	3.03	0.00	2.50	0.05	0.00	0.00	2.53	0.00	0.00	0.25	0.50	0.00	0.52	491	500			0	30.0
  RD-28	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00	1.01	0.00	0.25	0.50	2.58	0.52	490	500			0	30.0
  RD-29	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00		0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-30	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00		0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-31	500	3.03	0.00	2.50	0.05	0.00	0.00	0.00		0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-32	500	3.03	0.00	2.50	0.05	0.00	0.00		0.00	0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-33	500	3.03	0.00	2.50	0.05	0.00	0.00		0.00	0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-34	500	3.03	0.00	2.50	0.05	0.00	0.00		0.00	0.00	0.25	0.50	0.00	0.52	494	500			0	30.0
  RD-35	4000	24.24	0.00	20.00	4.08	0.00	0.00	0.00	0.00	0.00	2.02	4.02	0.00	4.12	3946	4000			0	30.0
  RD-36	4000	12.12	0.00	10.00	2.04	0.00	0.00	0.00	0.00	0.00	1.01	2.01	0.00	2.06	973	1000	1000		1000	30.0
  RD-37	500	0.00	0.00	2.50	0.51	0.00	0.00	0.00	2.53	0.00	0.25	0.50	0.00	0.52	494	500
  RD-38	500	3.03	0.00	2.50	0.51	0.00	0.00	0.00	2.53	0.13	0.25	0.50	0.00	0.52	494	500
  	500	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	500	500

  Ethanol-

  Triethanol-

  Formal-

  Potasium-

  Mercaptor-

  amine

  amine

  dehyde

  NH4Cl

  EDTA

  IAA

  sodium

  Isophthalic

  2,2'-

  ferro-

  NH4

  actetic

  Cu

  Final

  actual

  Klebosol

  Slurry

  (basic)

  (basic)

  (reducer)

  (leveler)

  (complex)

  (reducer)

  sulfite

  acid

  Dipyridyl

  ayanide

  cltrate

  acid

  SO4

  other

  pH

  pH

  1501-50

  Obervation

  RD-24	0.6		0.185	0.010						0.0190	0.1000		0.10		12.00	12.00
  RD-25	0.6		0.185	0.010						0.0500	0.0500		0.10		12.00	12.00
  RD-26	0.6		0.185	0.010				0.100		0.0500	0.1000		0.10	12.00	11.90
  RD-27	0.6		0.185	0.010			0.5000			0.0500	0.1000		0.10		12.00	12.00
  RD-28	0.6		0.185	0.010				0.2000		0.0500	0.1000	0.50	0.10		12.00	12.15		CuSo4 turn
  																		black at ph 8.8,
  																		desolved to
  																		color at ph 12,
  																		formed light
  																		brown color
  																		FeOH after
  RD-29	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.0
  RD-30	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.1
  RD-31	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.2
  RD-32	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.2
  RD-33	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.1
  RD-34	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00	12.0
  RD-35	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00
  RD-36	0.6		0.185	0.010						0.0500	0.1000		0.10		12.00		15.0
  RD-37			0.185	0.010				0.5000		0.0500	0.1000		0.10		12.00
  RD-38			0.185	0.010				0.5000	0.0250	0.0500	0.1000		0.10		12.00

• [0094]

  Appendix - Table 3

  Re-dep measurement Veeco

  RD-

  Pre

  Post

  DELTA

  formular	ASH	TIR	ASH	TIR	ASH

  RD-08
  RD-09
  RD-10
  RD-11
  RD-12
  RD-13
  RD-14
  RD-15	697	735	727	772	−30
  RD-16	517	699	522	706	−5
  RD-17	1034	1228	1008	1253	26
  RD-18	406	727	542	−14727	−136	Cu
  						spots
  RD-19	1285	1376	1235	1363	50
  RD-20	201	482	195	555	6
  RD-22	124	354	1	−44973	123	Cu
  						spots
  CA RD-09	309	342	−7970	−10527	8279	Re-dep
  CA RD-10	291	461	−32	−1374	323	Re-dep
  CA RD-18	1305	1385	781	1515	524	Re-dep
  CA RD-22	1732	1783	1411	1715	321	Re-dep
  RD-24	1101	1192	−1820	9354	2921	Re-dep
  RD-25	574	742	−477	2960	1051	Re-dep
  RD-26	404	472	−3764	5643	4168	Re-dep
  RD-27	79	197	181	248	−102
  RD-29	53	160	−8897	11935	8950	Re-dep	slot 12
  RD-30	1091	1229	−3630	6243	4721	Re-dep	slot 13
  RD-31	831	866	−3548	4717	4379	Re-dep	slot 14
  RD-32	929	959	910	1016	19		slot 15
  RD-33	1011	1231	−13273	22548	14284	Re-dep	slot 16
  RD-34	637	883	−4432	8563	5069	Re-dep	slot 17

• [0095]

  Appendix - Table 4

  RD-36 polish process

  wafer	DF(psi)	BP (psi)	Flow (ml/min)	Platen (rpm)	Carrier (rpm)	Pol. Time (sec.)	Slurry	Polish pad
  rd-pol5	3	1	150	85	80	30	RD-36	IC1000 xygroove
  	1	0	150	40	35	30	RD-36	IC1000 xy groove
  rd-pol6	3	1	150	85	80	15	RD-36	IC1000 xygroove
  	1	0	150	40	35	60	RD-36	IC 1000 xygroove
  touch polish
  	3	1	150	85	80	20	RD-36	IC1000 xygroove
  touch polish
  	1	0	150	40	35	30	RD-36	IC1000 xy groove
  rd-pol7	3	1	150	85	80	30	RD-36	Politex embossedpad
  	1	0	150	40	35	30	RD-36	Politex embossed pad
  rd-pol8	3	1	150	85	80	30	RD-36	Politex embossedpad
  	1	0	150	40	35	60	RD-36	Politex embossed pad

Claims (9)

What is claimed is:

1. A system for dished metal redevelopment of a semiconductor wafer by moving a surface of the wafer against a moving polishing pad, the system comprising the steps of:

providing a plating solution at an interface between the wafer and the polishing pad, which redevelops dished trenches in an interlayer dielectric, ILD, of the wafer by depositing metal onto the dished trenches; and

polishing the wafer with a relatively reduced polishing pressure to polish metal being deposited onto the dished trenches.

2. The system as recited inclaim 1 wherein, the step of providing a plating solution at the interface further comprises the step of; providing a plating solution comprised of, an electrolyte of metal ions, a metal-ion complexing agent, an adjusted pH greater than about 9, and a reducing agent.

3. The system as recited inclaim 1 wherein, the step of polishing the wafer with a relatively reduced polishing pressure further includes the step of: removing the plated metal to substantially the same planar level as the surface of a metal-migration barrier film on the ILD.

4. A system for dished metal redevelopment of a semiconductor wafer by moving the wafer against a moving polishing pad, and providing a polishing fluid at an interface of the wafer and the polishing pad during polishing, the system comprising the steps of:

polishing the wafer with a relatively higher polishing pressure for a time period sufficient to remove a top layer of metal over an underlying interlayer dielectric, ILD;

polishing the wafer with a reduced polishing pressure while providing a metal electroless plating solution at said interface, which redevelops dished trenches in the ILD by plating a top layer of plated metal onto the dished trenches, and by plating metal onto the underlying ILD that is removed to the level of the underlying ILD by polishing with the reduced polishing pressure.

5. A system for dished trench redevelopment of a semiconductor wafer by moving the wafer against a moving polishing pad, and providing a polishing fluid at an interface of the wafer and the polishing pad during polishing, the system comprising the steps of:

polishing the wafer with a relatively higher polishing pressure for a time period sufficient to remove a top layer of metal over an underlying interlayer dielectric, ILD, the ILD having dished trenches of imbedded metal to provide circuit interconnects;

polishing the wafer with a reduced polishing pressure while providing a plating solution at said interface, which redevelops the dished trenches by plating a layer of plated metal onto the dished trenches, and the step of polishing the wafer with a reduce polishing pressure further includes the step of polishing the layer of plated metal.

6. A system for dished metal redevelopment of a semiconductor wafer by moving a surface of the wafer against a moving polishing pad, the system comprising the steps of:

polishing the wafer with a relatively higher polishing pressure for a time period sufficient to remove a top layer of metal,

polishing the wafer with a reduced polishing pressure while providing a metal deposition solution at an interface between the wafer and the polishing pad, which redevelops dished trenches in the ILD by depositing metal onto the dished trenches, and by polishing the metal being deposited onto the dished trenches.

7. A polishing fluid for use in dished metal redevelopment by a CMP polishing operation wherein, a moving semiconductor wafer is urged against a moving polishing pad, the polishing fluid comprising: a metal deposition solution for depositing metal onto dished trenches in said wafer during said CMP polishing operation.

8. The polishing fluid as recited inclaim 7, wherein said solution further comprises, an electroless copper plating solution having CuSO₄, NH₄Cl, a reducing agent and an adjusted pH>9.

9. The polishing fluid as recited inclaim 7, wherein said solution further comprises, an electroless copper plating solution having CuSO₄, NH₄Cl, a reducing agent and an adjusted pH>11.

Images